This invention relates to an oven door of the type incorporating a window means for viewing the oven interior when the door is closed to observe the advance of the cooking process.
The oven door usually comprises a body portion including front and back metal panels having a substantially rectangular central opening therein in which the window means is mounted. It has heretofore been common practice to provide a window means comprising a double-glazed glass unit including two spaced, parallel, transparent glass panels, with a substantially dead air space therebetween. Although double-glazed window units of this character were designed to prevent transmission of oven heat, they did not function satisfactorily to maintain the outer exposed glass panel at the desired low temperature, particularly after the oven had been on for some period of time. To overcome this objection, a thin transparent reflective metal coating has been applied to the inner surface of the outer glass panel to reduce the transmittance of oven heat through the window. While these coatings have materially reduced the problem of excessive window temperature, they have not proven wholly successful in meeting the increasingly stringent standards required of the industry for lower window temperatures.
Another problem encountered with this type of oven door has been the relatively high temperature attained by the front metal door panel, particularly in the area above the window.
The present invention contemplates the provision of a multiple-glazed oven window unit which will effectively reduce the temperature not only of the outer exposed glass panel but also of the oven door proper and particularly that portion of the front metal door panel above the window.